A thermally-assisted magnetic recording (TAMR) write head simultaneously generates heat and a magnetic write field to the recording layer on a magnetic recording disk. The write head is located on the trailing face of a head carrier in a TAMR disk drive and comprises a single turn coil, part of which is a current strip having an edge located at the disk-facing surface of the head carrier. When write current is passed through the current strip heat is generated at the edge of the strip and a magnetic write field is induced at the disk surface. The strip edge has a predetermined width that substantially corresponds to the desired track width of the data bits. Because both heat and the magnetic write field are generated by the same element, the heat gradient and the magnetic write field gradient are co-located on the spot where the data bit is written.
|
7. A thin film write head for thermally assisted magnetic recording, comprising:
a substrate; a magnetic yoke on the substrate, the yoke comprising first and second pole pieces, each pole piece having a pole tip, the pole tips being spaced-apart to define a gap; and a coil layer located within the yoke for generating a magnetic field across the pole tips when current is passed through the coil, the coil layer including a strip located between the pole tips for generating heat when current is passed through the coil, the generated heat being sufficient to permit thermally assisted magnetic recording.
1. A write head for thermally assisted recording of data bits in tracks of a magnetic recording layer, comprising:
a head carrier having a recording layer facing surface and a trailing surface; and an electrically conductive coil having a single coil turn on the trailing surface, the single coil turn including a strip having an edge substantially at the recording layer facing surface and an edge width corresponding substantially to the data track width, so that when current is passed through the single coil turn a magnetic field and heat are generated at the edge of the strip, the generated heat being sufficient to elevate the temperature of the recording layer, thereby lowering its coercivity and permitting data bits to be more easily recorded by the magnetic field.
12. A magnetic recording disk drive, comprising:
a rotatable magnetic recording disk comprising a substrate and a magnetic recording layer on the substrate; a slider having a disk-facing surface and a trailing face and being maintained in proximity to the disk; and a thermally assisted magnetic write head formed on the trailing face of the slider and comprising a magnetic yoke having first and second pole pieces, each pole piece having a pole tip facing the disk, the pole tips being spaced-apart so as to define a write gap; a first spacer layer located in the gap adjacent the first pole tip; a second spacer layer located in the gap adjacent the second pole tip; and a coil layer located within the yoke between the first and second spacer layers, the coil layer including a primary coil turn between the pole tips for generating a magnetic field across the pole tips, the primary coil turn including a strip substantially at the disk facing surface for heating the magnetic recording layer on the disk, so that when electrical current is applied to the primary coil turn a magnetic field and heat are directed simultaneously to the recording layer on the disk, the temperature of the disk being raised sufficiently to decrease its coercivity, thereby permitting the magnetic field to more easily record data bits in the disk. 2. The head according to
3. The head according to
4. The head according to
5. The head according to
6. The head according to
8. The head according to
9. The head according to
10. The head according to
11. The head according to
13. The disk drive according to
14. The disk drive according to
|
This invention is related to application Ser. No. 09/608,848 filed Jun. 29, 2000 and entitled "Thermally-Assisted Magnetic Recording System with Head having Resistive Heater in Write Gap".
This invention relates to digital magnetic recording, and more particularly to a magnetic recording disk drive where data is written while the magnetic recording layer is at an elevated temperature.
Magnetic recording disk drives store digital information by using a miniaturized thin film inductive write head. The write head is patterned on the trailing face or surface of a head carrier, typically a slider that also has an air-bearing surface (ABS) to allow the slider to ride on a thin film of air above the surface of the rotating disk. The write head is an inductive head with a thin film electrical coil located between the pole pieces of a magnetic yoke. When write current is applied to the coil, the tips of the pole pieces provide a localized magnetic field across a gap that magnetizes regions on the recording layer on the disk into one of two distinct magnetic states that represent the recorded data bits.
The magnetic material for use as the recording layer on the disk is chosen to have sufficient coercivity such that the magnetized data bits are written precisely and retain their magnetization state until written over by new data bits. The data bits are written in a sequence of magnetization states to store binary information in the drive and the recorded information is read back with a use of a read head that senses the stray magnetic fields generated from the recorded data bits. Magnetoresistive (MR) read heads include those based on anisotropic magnetoresistance (AMR), giant magnetoresistance (GMR), such as the spin-valve type of GMR head, and the more recently described magnetic tunnel junction (MTJ) effect. Both the write and read heads are kept in close proximity to the disk surface by the slider's ABS, which is designed so that the slider "flies" over the disk surface as the disk rotates beneath the slider.
As the recording bit size decreases to increase the data density on the disk, a problem arises with the conventional thin film inductive write head and writing process that is referred to as the "superparamagnetic" effect. The areal data density (the number of bits that can be recorded on a unit surface area of the disk) of magnetic disk drives is approaching the point where the data bits are so small they can be demagnetized simply from thermal agitation within the magnetized bit (the so called the "superparamagnetic" effect). The conventional approach to circumventing this problem is to increase the magnetic anisotropy and coercivity of the magnetic material in the recording layer on the disk to improve the thermal stability. However, this requires that the write head be made with a material with high saturation moment to increase the write field of the head so the head can write on the high coercivity media. Based on the properties of known materials, the ultimate write field of the head can only be increased by about 30%, thus severely limiting future data density growth. In addition, the increased data rate required at higher areal density requires that the magnetic properties of the materials used in the write head have to be optimized, which is very difficult to achieve if the materials suitable for use are limited to only those that have a very high saturation moment.
Since it is known that the coercivity of the magnetic media (i.e., the magnetic recording layer on the disk) is temperature dependent, one proposed solution is "thermally assisted" magnetic recording (TAMR), wherein the magnetic material in the media is heated locally to near or above its Curie temperature during writing so that the coercivity is low enough for writing to occur, but high enough for thermal stability of the recorded bits at ambient temperature. Several approaches to TAMR have been proposed, including use of a laser beam or ultraviolet lamp to do the localized heating, as described in IBM Technical Disclosure Bulletin, Vol. 40, No. 10, October 1997, pp. 65-66, and IBM's U.S. Pat. No. 5,583,727. In these approaches, the heating area is typically wider than the data bit so that the data bit dimension is still determined by the size of the write head.
One of the problems still to be addressed in TAMR is the design of a write head that co-locates the heat and the magnetic write field to the same spot on the magnetic layer of the media, preferably to a region no larger than the size of the data bit to be recorded. A write head for use in a magneto-optic (MO) or TAMR system is described in U.S. Pat. No. 5,986,978, wherein a special optical channel is fabricated adjacent to the pole or within the gap of the inductive write head for thermally assisted writing of the MO or magnetic media by directing laser light or heat down the channel. IBM's previously cited application Ser. No. 09/608,848 describes a TAMR write head that uses a conventional thin film inductive write head and an electrically separated resistive heater located in the write gap between the pole tips of the inductive write head. The resistive heater directs heat to a region on the magnetic layer of the disk and the pole tips of the inductive write head direct the magnetic write field to the heated region. These TAMR head designs that use a separate heating element isolated from the inductive write coil require complex fabrication processes and/or electrical wiring layouts.
What is needed is a TAMR write head that co-locates heat and the magnetic write field and that is easier to fabricate and implement in a TAMR system than prior TAMR write heads.
The invention is a thermally-assisted write head to simultaneously generate heat and a magnetic write field to the magnetic recording layer on the disk, and a TAMR disk drive that uses the write head. The write head is located on the trailing face of a head carrier and comprises a single turn coil, part of which is a current strip having an edge located at the disk-facing surface of the head carrier. When write current is passed through the current strip heat is generated at the edge of the strip and a magnetic field is induced at the disk surface. The strip edge has a predetermined width that substantially corresponds to the desired track width of the data bits. Because both heat and the magnetic write field are generated by the same element, the heat gradient and the magnetic write field gradient are co-located on the spot on the recording layer where the data bit is written. In a second embodiment a magnetic yoke surrounds the single turn coil with the current strip located in the write gap between the pole tips of the yoke, so that current through the strip also induces a magnetic write field across the pole tips. In a third embodiment the single turn coil is the primary turn of a multi-turn coil, with the secondary coil turns located in the yoke but away from the current strip and the pole tips.
For a fuller understanding of the nature and advantages of the present invention, reference should be made to the following detailed description taken together with the accompanying figures.
Prior Art
Preferred Embodiments
The present invention is a TAMR write head that integrates the inductive write head and the thermal heating element into the same physical structure.
The current strip 20 is made of aluminum, copper or other metallic conductor. The total resistance and the magnetic field generating properties of strip 20 may be selected by design of the dimensions and material of the strip 20 and the current density through the strip. In one embodiment, the strip is made of aluminum with a thickness t of 800 nm, a height h of 100 nm and a width w of 150 nm, and the current density is 3.5×108 amps/cm2. This would generate a magnetic field of approximately 2000 Oe.
In this design of a TAMR write head, wherein the inductive write head and the resistive heater are integrated as a single element, the write head and heater are aligned physically, which thereby perfectly aligns the temperature gradient and the magnetic field gradient so that they are co-located to the same region on the media corresponding to the recorded data bit. In addition, the integrated TAMR head eliminates the use of magnetic material required for the inductive write head, i.e., the permalloy (NiFe) material used for the poles P2 and P1/S2 shown in the prior art
In the TAMR write head of
While the present invention has been particularly shown and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention. Accordingly, the disclosed invention is to be considered merely as illustrative and limited in scope only as specified in the appended claims.
Wickramasinghe, Hemantha K., Wu, Xiao Z., Moser, Andreas, Hsu, Yimin
Patent | Priority | Assignee | Title |
10957347, | Jan 10 2020 | International Business Machines Corporation | Thin film heating device in a write gap |
7070716, | Jul 28 2003 | Western Digital Technologies, INC | Method for providing transverse magnetic bias proximate to a pole tip to speed up the switching time of the pole-tip during the writing operation |
7072142, | Jul 28 2003 | Western Digital Technologies, INC | Apparatus for providing transverse magnetic bias proximate to a pole tip to speed up the switching time of the pole-tip during the writing operation |
7099096, | Feb 19 2003 | FUJI XEROX CO , LTD | Heat-assisted magnetic recording head and heat-assisted magnetic recording apparatus |
7268973, | Jul 24 2003 | HGST NETHERLANDS B V | Perpendicular magnetic head having thermally assisted recording element |
7755861, | Dec 06 2007 | Western Digital Technologies, INC | Method and system for providing a magnetic recording media |
7929248, | May 23 2006 | Seagate Technology LLC | Top bond pad for transducing head interconnect |
8325569, | Jun 27 2011 | Western Digital Technologies, INC | EAMR head having improved optical coupling efficiency |
8351158, | May 23 2006 | Seagate Technology LLC | Top bond pad for transducing head interconnect |
8456964, | Nov 16 2010 | Western Digital Technologies, INC | Energy assisted magnetic recording head having a reflector for improving efficiency of the light beam |
8625941, | May 20 2010 | Western Digital Technologies, INC | Broadband reflective waveguide metal gratings and their formation |
8670294, | Feb 17 2012 | Western Digital Technologies, INC | Systems and methods for increasing media absorption efficiency using interferometric waveguides |
8675455, | Feb 17 2012 | Western Digital Technologies, INC | Systems and methods for controlling light phase difference in interferometric waveguides at near field transducers |
8786984, | Nov 15 2011 | Western Digital Technologies, INC | Perpendicular magnetic write head having a current carrying element for in-plane field assisted magnetic recording |
8923102, | Jul 16 2013 | Western Digital Technologies, INC | Optical grating coupling for interferometric waveguides in heat assisted magnetic recording heads |
8947985, | Jul 16 2013 | Western Digital Technologies, INC | Heat assisted magnetic recording transducers having a recessed pole |
9064527, | Apr 12 2013 | Western Digital Technologies, INC | High order tapered waveguide for use in a heat assisted magnetic recording head |
9064528, | May 17 2013 | Western Digital Technologies, INC | Interferometric waveguide usable in shingled heat assisted magnetic recording in the absence of a near-field transducer |
9099108, | Jul 06 2011 | Seagate Technology LLC | Magnetically biased write pole |
9142233, | Feb 28 2014 | Western Digital Technologies, INC | Heat assisted magnetic recording writer having a recessed pole |
9190085, | Mar 12 2014 | Western Digital Technologies, INC | Waveguide with reflective grating for localized energy intensity |
9245562, | Mar 30 2015 | Western Digital Technologies, INC | Magnetic recording writer with a composite main pole |
9286920, | Jan 31 2013 | Western Digital Technologies, INC | Method for compensating for phase variations in an interferometric tapered waveguide in a heat assisted magnetic recording head |
9318132, | Apr 02 2014 | TDK Corporation | Magnetic head, magnetic head assembly, and magnetic recording and reproducing apparatus |
9336814, | Mar 12 2013 | Western Digital Technologies, INC | Inverse tapered waveguide for use in a heat assisted magnetic recording head |
9495984, | Mar 12 2014 | Western Digital Technologies, INC | Waveguide with reflective grating for localized energy intensity |
9697852, | Nov 06 2015 | Seagate Technology LLC | Single coil turn data writer |
Patent | Priority | Assignee | Title |
5909340, | Jan 03 1997 | Seagate Technology LLC | Hard disk drive having contact write and recessed magnetoresistive read head |
5986978, | Jan 12 1998 | Western Digital Technologies, INC | Read/write head and method for magnetic reading and magneto-optical writing on a data storage medium |
6016290, | Feb 12 1999 | Western Digital Technologies, INC | Read/write head with shifted waveguide |
6256171, | Sep 30 1996 | Kabushiki Kaisha Toshiba | Thin film magnetic head having an improved heat dispersion and magnetic recording apparatus using the same |
6317280, | Sep 26 1997 | Sharp Kabushiki Kaisha | Thermomagnetic recording and reproducing head having a heating head with a width narrower than the magnetic heads, a recording and reproducing device with such a heating head and methods related thereto |
6404706, | Feb 12 1999 | Western Digital Technologies, INC | Laser mounting for a thermally assisted GMR head |
6493183, | Jun 29 2000 | Western Digital Technologies, INC | Thermally-assisted magnetic recording system with head having resistive heater in write gap |
20010017820, | |||
JP2000030214, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Jul 12 2001 | MOSER, ANDREAS | International Business Machines Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 012039 | /0772 | |
Jul 12 2001 | WICKRAMASINGHE, HEMANTHA K | International Business Machines Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 012039 | /0772 | |
Jul 13 2001 | HSU, YIMIN | International Business Machines Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 012039 | /0772 | |
Jul 13 2001 | WU, XIAO Z | International Business Machines Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 012039 | /0772 | |
Jul 25 2001 | International Business Machines Corporation | (assignment on the face of the patent) | / | |||
Dec 31 2002 | MARIANA HDD B V | HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B V | CHANGE OF NAME SEE DOCUMENT FOR DETAILS | 015348 | /0191 | |
Dec 31 2002 | International Business Machines Corporation | MARIANA HDD B V | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 015370 | /0450 | |
Jul 23 2012 | HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B V | HGST NETHERLANDS B V | CHANGE OF NAME SEE DOCUMENT FOR DETAILS | 029341 | /0777 |
Date | Maintenance Fee Events |
Apr 08 2004 | ASPN: Payor Number Assigned. |
May 23 2007 | M1551: Payment of Maintenance Fee, 4th Year, Large Entity. |
May 29 2007 | ASPN: Payor Number Assigned. |
May 29 2007 | RMPN: Payer Number De-assigned. |
Jun 20 2011 | M1552: Payment of Maintenance Fee, 8th Year, Large Entity. |
Aug 07 2015 | REM: Maintenance Fee Reminder Mailed. |
Dec 30 2015 | EXP: Patent Expired for Failure to Pay Maintenance Fees. |
Date | Maintenance Schedule |
Dec 30 2006 | 4 years fee payment window open |
Jun 30 2007 | 6 months grace period start (w surcharge) |
Dec 30 2007 | patent expiry (for year 4) |
Dec 30 2009 | 2 years to revive unintentionally abandoned end. (for year 4) |
Dec 30 2010 | 8 years fee payment window open |
Jun 30 2011 | 6 months grace period start (w surcharge) |
Dec 30 2011 | patent expiry (for year 8) |
Dec 30 2013 | 2 years to revive unintentionally abandoned end. (for year 8) |
Dec 30 2014 | 12 years fee payment window open |
Jun 30 2015 | 6 months grace period start (w surcharge) |
Dec 30 2015 | patent expiry (for year 12) |
Dec 30 2017 | 2 years to revive unintentionally abandoned end. (for year 12) |